400 Wisconsin Academy of Sciences , Arts and Letters . 
Figure 1 shows the average development of an untwimmed individual. 
Mr. R. B. Green, late of the University of Wisconsin and now chemist 
for the Lake Superior Iron Company at Ishpeming, Michigan, has made 
an analysis of some of the more translucent crystals from Galena, Illinois,, 
with the following results: 
Calculated 
for Pb Co 3 . 
PbO. 83.42 83.52 
C0 3 .. 16.45 16.48 
99.87 100.00 
The material analyzed was specially examined for zinc with negative 
results. 
University of Wisconsin. 
